Kapt: Preserve parameter names for abstract methods

Author: yanex

compiler/backend/src/org/jetbrains/kotlin/codegen/TransformationMethodVisitor.java

@@ -70,7 +70,7 @@ public void visitEnd() {
             // So we just do it here
             if (methodNode.instructions.size() == 0
                 // MethodNode does not create a list of variables for abstract methods, so we would get NPE in accept() instead
-                && (!(delegate instanceof MethodNode) || (methodNode.access & Opcodes.ACC_ABSTRACT) == 0)
+                && (!(delegate instanceof MethodNode) || methodNode.localVariables != null)
             ) {
                 List<LocalVariableNode> localVariables = methodNode.localVariables;
                 // visits local variables

plugins/kapt3/src/org/jetbrains/kotlin/kapt3/Kapt3BuilderFactory.kt

@@ -21,12 +21,8 @@ import org.jetbrains.kotlin.codegen.ClassBuilder
 import org.jetbrains.kotlin.codegen.ClassBuilderFactory
 import org.jetbrains.kotlin.codegen.ClassBuilderMode
 import org.jetbrains.kotlin.resolve.jvm.diagnostics.JvmDeclarationOrigin
-import org.jetbrains.org.objectweb.asm.ClassWriter
-import org.jetbrains.org.objectweb.asm.FieldVisitor
-import org.jetbrains.org.objectweb.asm.MethodVisitor
-import org.jetbrains.org.objectweb.asm.tree.ClassNode
-import org.jetbrains.org.objectweb.asm.tree.FieldNode
-import org.jetbrains.org.objectweb.asm.tree.MethodNode
+import org.jetbrains.org.objectweb.asm.*
+import org.jetbrains.org.objectweb.asm.tree.*
 
 internal class Kapt3BuilderFactory : ClassBuilderFactory {
     internal val compiledClasses = mutableListOf<ClassNode>()
@@ -65,6 +61,12 @@ internal class Kapt3BuilderFactory : ClassBuilderFactory {
         ): MethodVisitor {
             val methodNode = super.newMethod(origin, access, name, desc, signature, exceptions) as MethodNode
             origins.put(methodNode, origin)
+
+            // ASM doesn't read information about local variables for the `abstract` methods so we need to get it manually
+            if ((access and Opcodes.ACC_ABSTRACT) != 0 && methodNode.localVariables == null) {
+                methodNode.localVariables = mutableListOf<LocalVariableNode>()
+            }
+
             return methodNode
         }
     }

plugins/kapt3/test/org/jetbrains/kotlin/kapt3/test/ClassFileToSourceStubConverterTestGenerated.java

@@ -186,6 +186,12 @@ public void testMapEntry() throws Exception {
         doTest(fileName);
     }
 
+    @TestMetadata("methodParameterNames.kt")
+    public void testMethodParameterNames() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("plugins/kapt3/testData/converter/methodParameterNames.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("methodPropertySignatureClash.kt")
     public void testMethodPropertySignatureClash() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("plugins/kapt3/testData/converter/methodPropertySignatureClash.kt");

plugins/kapt3/testData/converter/abstractMethods.txt

@@ -1,10 +1,10 @@
 public abstract class Base {
 
     protected abstract void doJob(@org.jetbrains.annotations.NotNull()
-    java.lang.String p0, int p1);
+    java.lang.String job, int delay);
 
     protected abstract <T extends java.lang.CharSequence>void doJobGeneric(@org.jetbrains.annotations.NotNull()
-    T p0, int p1);
+    T job, int delay);
 
     public Base() {
         super();

plugins/kapt3/testData/converter/mapEntry.txt

@@ -2,7 +2,7 @@ public abstract interface EntryHolder {
 
     @org.jetbrains.annotations.NotNull()
     public abstract java.util.Map.Entry<java.lang.String, java.lang.Object> entry(@org.jetbrains.annotations.NotNull()
-    java.util.Map.Entry<? extends java.lang.CharSequence, ? extends java.util.Map.Entry<java.lang.String, java.lang.Integer>> p0);
+    java.util.Map.Entry<? extends java.lang.CharSequence, ? extends java.util.Map.Entry<java.lang.String, java.lang.Integer>> p);
 
     @org.jetbrains.annotations.NotNull()
     public abstract java.util.Map.Entry<java.lang.String, java.lang.Object> getEntryProperty();

plugins/kapt3/testData/converter/methodParameterNames.kt

@@ -0,0 +1,15 @@
+interface Intf {
+    fun foo(abc: String)
+
+    fun bar(bcd: Int): String {
+        return ""
+    }
+}
+
+abstract class Cls {
+    abstract fun foo(abc: String)
+
+    fun bar(bcd: Int): String {
+        return ""
+    }
+}

plugins/kapt3/testData/converter/methodParameterNames.txt

@@ -0,0 +1,38 @@
+public abstract class Cls {
+
+    public abstract void foo(@org.jetbrains.annotations.NotNull()
+    java.lang.String abc);
+
+    @org.jetbrains.annotations.NotNull()
+    public final java.lang.String bar(int bcd) {
+        return null;
+    }
+
+    public Cls() {
+        super();
+    }
+}
+
+////////////////////
+
+
+public abstract interface Intf {
+
+    public abstract void foo(@org.jetbrains.annotations.NotNull()
+    java.lang.String abc);
+
+    @org.jetbrains.annotations.NotNull()
+    public abstract java.lang.String bar(int bcd);
+
+    public static final class DefaultImpls {
+
+        public DefaultImpls() {
+            super();
+        }
+
+        @org.jetbrains.annotations.NotNull()
+        public static java.lang.String bar(Intf $this, int bcd) {
+            return null;
+        }
+    }
+}